Posted
by
Zonk
on Thursday February 15, 2007 @05:34PM
from the any-mission-you-can-walk-away-from-right dept.

Sparky writes "Japan is planning to set the Hayabusa spacecraft on a trajectory back to Earth next month after a delay of more than a year, but it's far from certain that it will get back safely. It was supposed to retrieve asteroid debris, but it's thought that a computer error prevented that from happening. A fuel leak means that its chemical thrusters are out of action, and the craft is relying on its weaker ion engines. The journey back will take 3 years, and the capsule will be on Earth in June 2010 — even if it is empty."

As the summary clearly indicates, they're not 100% sure wtf is up with it. Bringing it back allows them to figure that out, as well as collect any asteroid debris it might have successfully picked up. In addition, they'll be able to track down the computer error to avoid it occurring in future craft. Same with the fuel leak.

Its highly likely that none of the parts that malfunctioned will be contained within the reentry package - theres no point in having those parts retrievable, all you want is the science package so thats all you bring to the ground. The rest will burn up in the atmosphere after seperation.

They are going through with the reentry because theres a chance they did get some debris, and they want to see if the reentry procedure works.

Because they spent however million building a ship capable of a return voyage.It will be wasted if they just give up.I think this is invaluable research and has taken a tremendous effort by the crew to even get this far.There may not be humans on-board this time but years in the future someone may end up being saved by lessons learnt in the Hayabusa incident.

Basically, the technology to retrieve a satellite from where it is now is likely just as hard as the original mission. Additionally, by the time retrieval would be possible, what would be the point? Technology marches ever on; even if they could retrieve Hayabusa, it's old technology now.

Additionally, such probes are one-shot devices. The components are built to specs to survive hard solar radiation, exposure to space, and all the extreme temperatures involved. I'd venture to guess they'd have to basically rebuild the satellite almost completely to be able to make another attempt with it. It's cheaper to just start from scratch and include the advances available to you.

Now, why bother trying to get it home? It's by no means as important as Apollo 13 (in that no lives are depending on it), but to take a probe that's seen better days and get it all the way back home in the face of what appear to be nearly insurmountable odds has quite a bit of sentimental value. For Japan to get Hayabusa home even in such a depleted state, it would be a great honor to their scientists. (And the fact that there's still *some* chance, albeit very small, that there may have been some material captured just makes it that much better.)

It's the "Incredible Journey" of satellites, or perhaps more apropos, it's the wounded samurai doing everything he can to make it back home before he dies. Very Japanese, and quite a good potential story, too.:)

Exactly. Sometimes you want to do something just to see if you can do it. If we didn't have people with attitudes like that, where would open source software be? A lot of these guys write code just because they want to see if they could do it. Linus is a perfect example. He didn't set out to dominate the world. He set out to see if he could write a UNIX-like kernel -- and he did. This sort of thinking leads to bigger and better things later. In Linus' case, we have a world-class enterprise-ready op

There is no "parking" orbit in the way you would imagine. The re-entry vehicle will be on a high-speed direct-entry trajectory from its inter-planet course. That is part of the challenge and and a reason to attempt it even if the capsule might be empty.

Just sound cool. The Hayabusa is powered by four xenon Ion Engines. It is using xenon ions generated by microwave ECR, and a Carbon / Carbon-composite material for acceleration grid which is resistant to erosion.

The navigation systems shut down for 13 months, only 2/16 engines work reliably, 2/3 of the wheels failed and pellet gyn failed to fire. Yet they're bringing it back to Earth "in case some asteroid dust had slipped into its collection chamber by chance."
Because they're feeling lucky?

The navigation systems shut down for 13 months, only 2/16 engines work reliably, 2/3 of the wheels failed and pellet gyn failed to fire. Yet they're bringing it back to Earth "in case some asteroid dust had slipped into its collection chamber by chance." Because they're feeling lucky?

If that many things break, but you can still drive it back to Earth, then you are certainly "lucky".

"Only 2/16 engines work reliably, 2/3 of the wheels failed"... and its STILL better than anything Detroit makes. Now they're going to try crashing it into a planet to show NASA that they're not the only space agency capable of... crashing something into a planet. Japan was miffed when the European Space Agency got the drop on them last year and slammed something into the moon.

That's the first thing I thought of when I read the headline. I thought it was about someone modifying their Suzuki to fly at those speeds (200+ mph) and then finally getting the landing correct. I guess Hayabusa is a common name in Japan like Mike is here in the US.

Turbobusa. If that's wrong, I don't want to be right. I couldn't imagine the rush of that, personally I don't like the big heavy bikes but I'd make an exception for that experience. The first time I threw a leg over an RS125 two-stroke GP bike and did a few track days with a buddy of mine, even the nicest street bikes started feeling clunky and unresponsive. But that boosted Hayabusa would be like nothing else for sheer straight-line velocity.

Maybe we can get some more usefulness out of the spacecraft still. Crash it into something, the moon, an asteroid, the sun? I'm not really sure if the satellite has enough fuel to do any of those things, but it's worth a try. Better, I think, than returning an empty capsule to Earth.

No, I'll bet they'll find alien spam. Of all the products that humans produce, spam seems to get into more things and go further than anything else. Thus, I expect our First Contact with aliens will be alien mortgage discounts or Ziagra pills.

...but it's thought that a computer error prevented that from happening...

Maybe they didn't have patch their WINDOWS and got BSOD (Blue Screen Of Death)
Which is quite funny... cause I've never seen a dedicated computer running Linux which crashed due to Kernel Panic
Quite a funny thought:]

They should smash it against a comet. There is nothing to bring back anyway. Why now use it to extract useful spectrum data instead? Especially if they are out of fuel, there will be less noise the organics lines, assuming the standard hydrazine propellant. We already know that ion engines work, what are they trying to show? On the other hand, we know that there are organics in comets but we don't know much more than that. Beside, smashing stuff is always fun.

They should smash it against a comet. There is nothing to bring back anyway.

They don't know that yet. Even though they know debri collection gizmo didn't work as planned, there may still be some *residue* debri to analyze due to the bumping motion. Small samples are better than no samples.

Plus, I don't think it's navigational capabilities are designed for comet aiming. When you are approaching an object in a gradual fashion (such as the original asteroid), you can use images for incrimental course correc

A man with binoculars. That is how it began: with a man standing by the side of the road, on a crest overlooking a small Arizona town, on a winter night. Lieutenant Roger Shawn must have found the binoculars difficult. The metal would be cold, and he would be clumsy in his fur parka and heavy gloves.

A Hayabusa is a Japanese bird of prey which attacks other birds by diving at speeds over 200mph into their wings. It seems an appropriate name for a machine designed to land on an asteroid.
http://en.wikipedia.org/wiki/Hayabusa [wikipedia.org]

I think the Japanese Hayabusa will be in better shape after it crashes, though.:-)

The rear cowling looks like a giant phallus to me - that'd be putting it politely tho.

Got a GSXR myself, looks half decent and is a hell of a lot more comfortable... altho it still sucks for long trips... but yeah not only is the Hayabusa butt ugly... it looks nothing like it's namesake.:( Shame, it really needs a more aggressive style.

If you read the timeline of hayabusa's journey it has just been incredible how many things failed. I mean, practically everything imaginable went wrong with this thing. I wouldn't be surprised if their primary purpose in bringing it back was simply to salvage a modicum of dignity. Seriously. They able to upload and download its software. That should be enough to tell a lot about what was wrong with it. I mean, it's not as if they can't tell probably 90% of what they problems were just through data. I'm guessing they're just bringing it back for the sake of at least being able to claim that they got a spacecraft, that was designed to go somewhere and then come back, to actually come back, even if it didn't fulfill any of the purposes for which its coming back was to be useful.

I think it is a sign of grandeur that even though much has failed (in a series of events that can only be described as a series of bad, bad incidents), they are still not abandoning the project. They started something, and they stick with it.

Then again, I've always had a weak spot for stories in which broken stuff is brought back to life.

Ion Drives are not slow. And Japan is probably most interested in how the drives perform.

From Deep Space 1;

The ultimate speed of a spacecraft using ion thrust depends upon how much propellant it carries; indeed, the same principle applies to chemical propulsion systems, although they are much less efficient. The ion propulsion system on Deep Space 1 carries about 81.5 kilograms of xenon propellant, and it takes about 20 months of thrusting to use it all. It increases the speed of the spacecraft by about 4.5 kilometers per second, or about 10,000 miles per hour. If we had the same amount of chemical propellant, it would provide only one tenth as much velocity increment. If DS1 carried a larger solar array, it certainly would have a slightly higher acceleration, and if it carried more Xe propellant it could reach a much higher final velocity by simply thrusting longer. But DS1 is testing ion propulsion solely to find out if it works as well as predicted. Future missions that use it likely will carry more propellant to achieve still higher speeds.